3.5.0 doesn't support SphinxSE

[sanikolaev]

Protocol autodetection introduced in 3.5.0 broke integration with SphinxSE, because the server expects the client (SphinxSE mysql engine) to send smth to detect the protocol, but SphinxSE just opens a connection and waits, then a timeout occurs:

Table in MariaDB:

CREATE TABLE `t2` (  
  `id` bigint(20) unsigned NOT NULL,  
  `weight` int(11) NOT NULL,  
  `query` varchar(3072) NOT NULL,  
  `group_id` int(11) DEFAULT NULL,  
  KEY `query` (`query`(768))  
) ENGINE=SPHINX DEFAULT CHARSET=utf8mb4 CONNECTION='sphinx://localhost:9312/test'  

Fail on select:

MariaDB [test]> reset query cache; SELECT * FROM t2 WHERE query='abc;mode=any';  
Query OK, 0 rows affected (0.000 sec)  
  
ERROR 1429 (HY000): Unable to connect to foreign data source: failed to receive searchd version (host=localhost, port=9312)  

TCP:

root@de5b82db934c:/# tshark -i lo  
Running as user "root" and group "root". This could be dangerous.  
Capturing on 'Loopback: lo'  
    1 0.000000000    127.0.0.1 ? 127.0.0.1    TCP 74 38090 ? 9312 [SYN] Seq=0 Win=43690 Len=0 MSS=65495 SACK_PERM=1 TSval=2245266117 TSecr=0 WS=128  
    2 0.000017925    127.0.0.1 ? 127.0.0.1    TCP 74 9312 ? 38090 [SYN, ACK] Seq=0 Ack=1 Win=43690 Len=0 MSS=65495 SACK_PERM=1 TSval=2245266117 TSecr=2245266117 WS=128  
    3 0.000038199    127.0.0.1 ? 127.0.0.1    TCP 66 38090 ? 9312 [ACK] Seq=1 Ack=1 Win=43776 Len=0 TSval=2245266117 TSecr=2245266117  
    4 5.004664723    127.0.0.1 ? 127.0.0.1    TCP 66 9312 ? 38090 [FIN, ACK] Seq=1 Ack=1 Win=43776 Len=0 TSval=2245271121 TSecr=2245266117  
    5 5.004720188    127.0.0.1 ? 127.0.0.1    TCP 66 38090 ? 9312 [FIN, ACK] Seq=1 Ack=2 Win=43776 Len=0 TSval=2245271121 TSecr=2245271121  
    6 5.004737245    127.0.0.1 ? 127.0.0.1    TCP 66 9312 ? 38090 [ACK] Seq=2 Ack=2 Win=43776 Len=0 TSval=2245271121 TSecr=2245271121  

The idea is to add a new listen protocol "sphinxse" especially for SphinxSE.

[githubmanticore]

Bypass for SphinxSE

That is kind of 'gray area' in sphinx binary protocol handshake, namely:
who speaks first after connect? Usually order is not important, just the
fact that both send the handshake. But SpinxSE explicitly wait daemon
to speak first.

That fixes #379 on github, and fixes #1520 via commit c385c41

[githubmanticore]

Merge branch 'sphinxse_fix' into 'master'

Sphinxse fix

Closes #1520 and #379

See merge request manticoresearch/dev!89 via commit 4962b10